From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D332C2B9F7 for ; Wed, 26 May 2021 04:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DDF26117A for ; Wed, 26 May 2021 04:33:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232011AbhEZEej (ORCPT ); Wed, 26 May 2021 00:34:39 -0400 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:52735 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229644AbhEZEeg (ORCPT ); Wed, 26 May 2021 00:34:36 -0400 X-Greylist: delayed 99047 seconds by postgrey-1.27 at vger.kernel.org; Wed, 26 May 2021 00:34:35 EDT Received: (Authenticated sender: josh@joshtriplett.org) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id 1326BC0003; Wed, 26 May 2021 04:32:49 +0000 (UTC) Date: Tue, 25 May 2021 21:32:47 -0700 From: Josh Triplett To: "Eric W. Biederman" Cc: Menglong Dong , Luis Chamberlain , Alexander Viro , Kees Cook , Sami Tolvanen , ojeda@kernel.org, johan@kernel.org, Bjorn Helgaas , masahiroy@kernel.org, Menglong Dong , joe@perches.com, Jens Axboe , hare@suse.de, Jan Kara , tj@kernel.org, gregkh@linuxfoundation.org, song@kernel.org, NeilBrown , Andrew Morton , f.fainelli@gmail.com, arnd@arndb.de, Rasmus Villemoes , wangkefeng.wang@huawei.com, Barret Rhoden , mhiramat@kernel.org, Steven Rostedt , vbabka@suse.cz, Alexander Potapenko , pmladek@suse.com, Chris Down , jojing64@gmail.com, terrelln@fb.com, geert@linux-m68k.org, mingo@kernel.org, linux-fsdevel@vger.kernel.org, LKML , jeyu@kernel.org Subject: Re: [PATCH v2 2/3] init/do_cmounts.c: introduce 'user_root' for initramfs Message-ID: References: <20210525141524.3995-1-dong.menglong@zte.com.cn> <20210525141524.3995-3-dong.menglong@zte.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, May 25, 2021 at 10:23:09PM -0500, Eric W. Biederman wrote: > If we are going to do this something that is so small and clean it can > be done unconditionally always. [...] > The net request as I understand it: Make the filesystem the initramfs > lives in be an ordinary filesystem so it can just be used as the systems > primary filesystem. Including the ability to pivot_root it away, which seems like the main sticking point. If this can be done without any overhead, that seems fine, but if this involves mounting an extra filesystem, that may add an appreciable amount of boot time for systems trying to boot in milliseconds. (Such systems would not use an initramfs if they're going to go on and boot a separate root filesystem, but they can use an initramfs as their *only* filesystem.)